1. Field of the Invention
An embodiment disclosed herein relates to a teaching system, a teaching method and a robot system.
2. Description of the Related Art
Conventionally, there have been proposed different kinds of teaching systems which graphically display a three-dimensional model image of a robot system on a display device based on three-dimensional CAD (Computer Aided Design) data and which operate the three-dimensional model image to prepare teaching data by carrying out simulative calculation of a motion of the robot system (see, e.g., Japanese Patent Application Publication No. 2000-20120).
By using the teaching systems mentioned above, an operator can prepare teaching data while verifying whether a robot interferes with surrounding equipment, without having to actually operate the robot and the external axes thereof.
For example, a “robot teaching system” disclosed in Japanese Patent Application Publication No. 2000-20120 is designed to perform off-line teaching by preparing teaching data for a welding robot system including a welding robot and a workpiece positioning device (hereinafter referred to as a “positioner”).
However, the conventional teaching systems mentioned above, which pertain to the teaching of a welding robot system, has a room for improvement in that a welding line needs to be easily kept horizontal so as to improve a welding quality.
More specifically, a need has conventionally existed in a welding work to keep horizontal the portion of a welding line where a welding work is carried out, thereby preventing a welding bead from flowing down under the action of the gravity. To this end, it is required to perform fine and precise teaching for appropriately changing the position and posture of a workpiece in conformity with the shape of different welding lines with respect to a positioner.
For example, if the positioner has a plurality of axes such as two axes of a tilting axis and a rotation axis or the like, the teaching for keeping the welding line horizontal becomes highly abstruse. For that reason, it is very burdensome for the operator to manually keep the welding line horizontal on the work spot. In the case of off-line teaching, the procedures are complex.
The conventional teaching systems mentioned above fail to disclose or suggest a method of keeping the welding line horizontal. Thus, when performing the teaching of a welding robot system, there is a need to easily keep a welding line horizontal and to improve a welding quality.
In addition to the welding robot system, it is sometimes necessary in, e.g., a sealing robot system including a sealing robot and a positioner, to keep a sealing portion horizontal and to improve a sealing material application quality.